Chris, That's what Fred Brooks, Jr. who was in charge of the IBM 360 project said in a speech. I just tried to transcribe it because I thought it was so interesting. He has a nice way of talking about things which may explain his use of the word "magic".
I understand your point. I always thought those extra spaces were for sequence numbers, too. I don't know what a 701 card reader is or what Fred is talking about with 36+36. Maybe it started that way and then later they had the extra after 72 to use as sequence numbers? I dunno. I love the history of this though. Regards, Lindy -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Chris Mason Sent: Thursday, October 12, 2006 2:28 AM To: [email protected] Subject: Re: What's a "programming language" (was: Google ... ) Lindy I'm a bit puzzled over your column 73. The "troublesome" column in Assembler - and JCL in its early days - and any definition schemes that have managed to get tied to the Assembler format, such as VTAM, is column 72. With all the "card" formats, the expectation was that human hands are unsteady and sometimes decks of cards get dropped on the polished tiles of the raised floor and scatter far and wide. Thus there was provision for a sequence number in columns 73 to 80. Another "troublesome" column was 16 which was where continued data was expected to resume in JCL before the restriction was relaxed to just having one blank between the "//" and the continuation data. I really can't remember whether or not this was required in Assembler or just conventional given the maximum 8 character name and the allowance of 5 characters for the "verb/instruction/macro". How *** the word "magic" could ever be applied to any of this ... Chris Mason ----- Original Message ----- From: "Lindy Mayfield" <[EMAIL PROTECTED]> Newsgroups: bit.listserv.ibm-main To: <[email protected]> Sent: Tuesday, 10 October, 2006 2:35 PM Subject: Re: What's a "programming language" (was: Google ... ) > There was a very interesting talk from Fred Brooks at the computer history museum's 40th anniversary of the 360. > > Here is my transcription of his talk about JCL (pardon any mistakes): > > ... > But it wasn't exactly like the assembler. And it was card column dependent. Column 73 was magic. And for years afterwards you sit down to a terminal and you wonder why column 73. Well it had to do with the fact that the cards on a 701 read in two sets of 36 bits and that used 72 columns. And JCL still preserves this column dependence. > ... ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
